Re: [Qemu-devel] [Qemu-block] [PATCH v5 08/12] block: Add "drained begin/end" for transactional blockdev-backup

[Jeff Cody <jcody@redhat.com>]

On Wed, Oct 21, 2015 at 10:06:45AM +0800, Fam Zheng wrote:
> Similar to the previous patch, make sure that external events are not
> dispatched during transaction operations.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  blockdev.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/blockdev.c b/blockdev.c
> index 0a7848b..52f44b2 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -1756,6 +1756,11 @@ static void blockdev_backup_prepare(BlkTransactionState *common, Error **errp)
>          return;
>      }
>  
> +    if (!blk_is_available(blk)) {
> +        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, backup->device);
> +        return;
> +    }
> +
>      target = blk_by_name(backup->target);
>      if (!target) {
>          error_setg(errp, "Device '%s' not found", backup->target);
> @@ -1770,6 +1775,8 @@ static void blockdev_backup_prepare(BlkTransactionState *common, Error **errp)
>          return;
>      }
>      aio_context_acquire(state->aio_context);
> +    state->bs = blk_bs(blk);
> +    bdrv_drained_begin(state->bs);
>  
>      qmp_blockdev_backup(backup->device, backup->target,
>                          backup->sync,
> @@ -1782,7 +1789,6 @@ static void blockdev_backup_prepare(BlkTransactionState *common, Error **errp)
>          return;
>      }
>  
> -    state->bs = blk_bs(blk);
>      state->job = state->bs->job;
>  }
>  
> @@ -1802,6 +1808,7 @@ static void blockdev_backup_clean(BlkTransactionState *common)
>      BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
>  
>      if (state->aio_context) {
> +        bdrv_drained_end(state->bs);
>          aio_context_release(state->aio_context);
>      }
>  }
> -- 
> 2.4.3
> 
> 

Reviewed-by: Jeff Cody <jcody@redhat.com>